[MPlayer-dev-eng] playing AC3 through HDMI abnormal sound issue
AnnieLiu at viatech.com.cn
AnnieLiu at viatech.com.cn
Fri Nov 25 13:02:39 CET 2011
Dear All
I am Annie Liu from VIA Technology. I met an issue when play ac3 through HDMI by mplayer and need your help.
I added the codec patch into alsa-driver to support our HDMI audio and I declared it as “HDA_PCM_TYPE_HDMI”. It works fine when play wav file.
Now, I met an issue when playing audio with AC3 format through HDMI.
If I use VLC (A52->S/PDIF), the sound is Okay, and the audio format displayed on amplifier is “D” (Dolby) as well. But I use mplayer with option “-ac hwac3”, the audio sounds abnormal, although the amplifier display “D” (Dolby). I tried mplayer with “-ac a52”, but I found it decode AC3 to PCM.
On the contrary, if I try “-ac hwac3” on a “digital codec” in our SB which declared as “HDA_PCM_TYPE_SPDIF”, the sound is fine; but if I use VLC (A52->S/PDIF) no sound outputted.
In VLC, I also found some a52 libraries:
/usr/lib/vlc/plugins/codec/liba52_plugin.so
/usr/lib/vlc/plugins/audio_filter/liba52tospdif_plugin.so
I wonder how I can play ac3 by mplayer through HDMI in Dolby?
I tried to declare my HDMI as “HDA_PCM_TYPE_SPDIF” in codec patch, the abnormal issue happened as well. (Playing PCM is Okay).
I wonder if the audio data encoded by hwac3 is compatible with HDMI.
I searched a lot of topics related to playing ac3 through HDMI, and found someone said I should set AES0 as 0x02. I did it by iecset, it works. But when I play ac3 by mplayer, it always reports “[AO-ALSA] alsa-lib: pcm.c:2208: (snd_pcm_open_noupdate) Unknown PCM hw:0,3,AES0=6”. I don’t know why it happens.
Could anyone give me favor on it?
Thanks a lot in advance!
Thanks a lot.
BR//Annie
Annie Liu (刘晓丽)
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Software Team, 5th Floor, VIA Technologies (China) Inc., Ltd.
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Tel: 86-10-59852288 ext. 3865
E-mail: annieliu at viatech.com.cn <blocked::mailto:annieliu at viatech.com.cn>
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